摘要： 并行查询执行计划的搜索空间里指数级增长，如何高效地裁剪搜索空间是并行查询优化的关键所在。ＰＢＡＳＥ／２以流机制为基础，采用基于代价估算和启发式规则的改良的两阶段优化技术，有效地解决了这一问题。

关键词: 并行查询优化, 流机制, 并行数据库

Abstract: The search space of parallel query execution plan is exponential complexity. How to prune the search space efficiently is the key problem of parallel query optimization. PBASE/2 is based on stream mechanism. It uses an improved two-phase approach based on cost estimation and heuristics to solve this problem effectively.

中图分类号: 

• TP311.13